In the humidification process, steam is normally discharged from a steam source as a dry gas or vapor. As steam mixes with cooler duct air, some condensation takes place in the form of water particles. Within a certain distance, the water particles are absorbed by the air stream within the duct. The distance wherein water particles are completely absorbed by the air stream is called absorption distance. Another term that may be used is a non-wetting distance. This is the distance wherein water particles or droplets no longer form on duct equipment (except high efficiency air filters, e.g.). Past the non-wetting distance, visible wisps of steam (water droplets) may still be visible, for example, saturating high efficiency air filters. However, other structures will not become wet past this distance. Absorption distance is typically longer than the non-wetting distance and occurs when visible wisps have all disappeared and the water vapor passes through high efficiency filters without wetting them. Before the water particles are absorbed into the air within the non-wetting distance and ultimately the absorption distance, the water particles collecting on duct equipment may adversely affect the life of such equipment. Thus, a short non-wetting or absorption distance is desirable.
The conventional configuration of steam dispersion systems used to achieve a short non-wetting or absorption distance consists of multiple, closely spaced dispersion tubes. The number of tubes and their spacing are based on the needed non-wetting or absorption distance. The dispersion tubes can get very hot (e.g., around 212 F on outer surface). A large number of hot tubes heat the duct air, resulting in wasted energy in the cooling and humidification process. Moreover, cool air (e.g., at 50-70 F) flowing around the hot dispersion tubes condenses a portion of the steam within the dispersion tubes. The condensate is often wasted to a drain.
What is needed in the art is an insulation material that can be used with the steam dispersion tubes and other parts of a steam dispersion system that effectively reduces condensate and heat gain, which is also easy to attach.